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Fatigue damage ship structures is of an essentially local nature and, in the case of damage to members, may frequently go unnoticed for a prolonged period. The occurrence of damage in any region of the structure generally entails a local stress increase in neighbouring regions and consequently their more rapid failure. A separate problem is damage to the shell plating, which can lead to hazardous failures particularly in the case of high-speed vessels. Selection of fatigue-damage repair method depends in each specific instance on an analysis of damage causes. In most cases encountered, the most effective damage repair methods are those involving replacement of the entire assembly, especially in conjunction with appropriate structural changes. When evaluating the extent of structural replacement, the effect pattern of indentations must be considered, i.e., insert welds should be localised beyond regions of structural indentations and high stresses. During repair procedures, principles of minimising the introduction of process stresses by selection of correct assembly and welding techniques should be observed.